title: An association between IL-9 and IL-9 receptor gene polymorphisms and atopic dermatitis in a Korean population.
abstract: BACKGROUND
  The genes encoding IL-9 and IL-9R have recently been implicated in the genetic basis of asthma and allergy. Although studies performed on transgenic and knockout mice have shown conflicting results, no evidence of skin changes has ever been reported in these animals.
  
  
  OBJECTIVE
  To find association of the SNPs in IL-9 and IL-9R genes and interaction of these genes in atopic dermatitis.
  
  
  METHODS
  We genotyped 5 SNPs from the IL-9 and IL-9R genes of 1090 subject samples (631 AD patients and 459 normal controls). A luciferase assay was then performed for the rs31563 (-4091G/A) SNP located in the IL-9 gene promoter region.
  
  
  RESULTS
  The rs31563 (-4091G/A) SNP in the IL-9 gene was significantly associated with the AD phenotype, especially allergic-type AD. In the luciferase assay, the rs31563 G construct was observed to have 1.54 times higher activity than the rs31563 A construct. Although no association was found between SNPs in IL-9R gene and AD, the rs3093467 SNP showed association with non-allergic AD. In the gene-gene interaction analysis, we found that IL-9/IL-9R genotype rs31563 GG/rs3093467 TT conveyed a greater risk for AD phenotype development.
  
  
  CONCLUSIONS
  Significant evidence exists to suggest that the rs31563 SNP (-4091G/A) located in the IL-9 gene is associated with an increased susceptibility to AD. Similarly, the rs3093467 SNP in IL-9R gene seems to be associated with an increased risk for developing non-allergic AD. In a subsequent gene-gene interaction analysis, the rs31563 GG/rs3093467 TT genotype combination (IL-9/IL-9R) was found to exert a synergistic effect in the development of the AD phenotype. As the classes of helper T cells are diverse and the function of IL-9 cytokine has not been fully described, the cutaneous function of IL-9 needs to be further explored in future studies.
authors.affiliation: Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Namkung
authors.forename: Jong-Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Eugene
authors.initials: E
authors.lastname: Kim
authors.forename: Geon Tae
authors.initials: GT
authors.lastname: Park
authors.forename: Hee Seung
authors.initials: HS
authors.lastname: Yang
authors.forename: Hye Yoon
authors.initials: HY
authors.lastname: Jang
authors.forename: Eun-Soon
authors.initials: ES
authors.lastname: Shin
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Cho
authors.forename: Jun-Mo
authors.initials: JM
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000483:Alleles; D002648:Child; D003876:Dermatitis, Atopic / Q000208:ethnology* / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D016906:Interleukin-9 / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D008957:Models, Genetic; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D053651:Receptors, Interleukin-9 / Q000378:metabolism*; D056910:Republic of Korea; D012867:Skin / Q000378:metabolism
chemical_list: D016906:Interleukin-9; D053651:Receptors, Interleukin-9; D008156:Luciferases